In a typical office environment, printed documents of various sorts are filed and stored in file cabinets, desks, shelves, drawers and other office furniture. Paper or plastic labels are affixed to the drawers or doors to describe the contents in a broad way. Labeled file folders or containers are used to group related papers in a drawer or on a shelf. In some sophisticated operations, indexes are manually created and maintained to record the documents that are supposed to be in each area, for example, card catalogs. If a document is erroneously filed, it may be lost for all practical purposes.
The retrieval of misplaced or lost files is time consuming and costly. In offices, warehouses and other facilities having large volumes of files, significant time and energy are frequently expended searching for missing or lost files.
In the past, a variety of systems have been implemented to track and control different sorts of objects, including files and printed documents. For example, in U.S. Pat. No. 6,407,665 issued to J. D. Stanfield et al. on May 12, 1998, which is incorporated by reference herein in its entirety, there is disclosed a tracking system including a processor which interfaces with a database, a plurality of file folder retainers and a plurality of file folders. The database includes file information, file location and a unique file address for the plurality of files in the system. The system actively maintains and updates the database by providing interactive communication between the processor, the folder retainers and the file folders. Communication is achieved by an electrical bus system to which the components are connected. Bus systems of this type are complicated, expensive to install and difficult to maintain in a typical office environment.
Radio frequency (RF) identification systems utilizing RFID tags are known in the art and are often used to identify an object and its location. In such a system, an RF signal is directed onto a tag attached to the object enabling the tag to emit a response. The system can determine from the response not only the identity of the object but also its location. RFID systems typically include an RFID reader or coupler, sometimes referred to as an “exciter”, and an RFID tag which is attached to the object. Since the typical RFID reader or exciter communicates with the tagged object by RF energy, the reader does not require a direct line-of-sight between the reader and the tagged object. The object may be located inside a closed box, cabinet or drawer and may still be identified by the RFID reader.
In recent years, RFID systems have been used for identifying many different kinds of objects such as vehicles, animals, parcels, laundry, railroad cars and warehouse inventories, for example. However, such systems have enjoyed only limited success in tracking files and documents in an office environment. A reason for this limitation may be the enormity of the task of attaching RFID tags to literally thousands, if not millions, of printed documents and files that are generated in a typical office. In addition to printing the documents, each tag must be individually “written to” or embedded with a unique code identifying the document as well as other data and information indicative of its location, category, etc., in a storage system. The tag must then be attached to the documents in a separate operation either by hand or by use of some mechanical device.
Another problem has been that office documents are typically stored in metal cabinets which impede RF transmission and make difficult reading RFID tags placed inside the cabinets. In U.S. Pat. No. 6,127,928 issued to M. Issacman et al. on Oct. 3, 2000, which is incorporated by reference herein in its entirety, this problem is addressed by employing a host transceiver which transmits a coded RF signal, at a first frequency, to a local RFID reader inside the metal cabinet. The local reader then retransmits the coded signal at a second frequency via an antenna. A passive RFID tag containing the same code and attached to a document inside the cabinet, when in the vicinity of the antenna, is energized by the RF field and modulates the second frequency signal from the local reader. The second frequency signal modulated by the energized tag is then directly received by the host transceiver. Although these patentees have provided a means for identifying documents held in metal cabinets, there still remains a need for changing or modifying the ID codes and/or other data in RFID tags attached to documents held in many different types of storage units
U.S. Pat. No. 6,407,665 issued to W. C. Maloney on Jun. 18, 2002, which is incorporated by reference herein in its entirety, discloses a document tracking system for locating file folders in a file cabinet having a plurality of drawers. The file folders are provided with inductive RFID tags and each drawer has an inductive loop antenna attached to the back of the drawer. The loop antenna is connected through flexible cabling to a controller. The other drawers of the cabinet are similarly provided with an antenna which are all coupled to the same controller by means of an electrical buss. A user can request the controller to poll all of the file folders in each drawer to determine if any folders are missing. However, there is still a need to change or modify the data stored in each RFID tag held in the file cabinet.